Although atazanavir received approval in the US for treatment of both naïve and experienced patients, approval in Europe was for treatment-experienced patients only. Nevertheless many clinics are using ritonavir-boosted atazanavir as first-line treatment, and as preferntial choice for switching patinets intollerant to efavirenz. Atazanavir requires once-daily dosing, has a low pill count and has good reported tolerability.
Holmes and colleagues from the Chelsea and Westminster Hospital, the UK’s largest clinic, presented results from a prospective review of 241 patients who switched to atazanavir during the last 12 months (all but ten using ritonavir boosting). 89/241 patients were PI-naïve, 47 were single-PI experieced and 105 were multiple PI-experienced. Reasons for switching included adverse drug reaction (78), end of trial (28) and adherence (9).
At week 48, by intent-to-treat analysis 60% and 57% of PI-naïve and PI-experienced patients respectively achieved viral suppression <50 copies/mL, (72% and 64% were <500 copies/mL). Patients changing due to virological failure had a mean viral load decrease of –2.1 and –1.9 logs in the naïve and experienced groups respectively. Rate of hypecholesterolaemia (>6.5mmol/L) dropped form 15% to 9% of patients. Mean bilirubin increase was 24 mmol/L with four patients discontinuing atazanavir due to jaundice.
Ref: Holmes PM, Tung M, Bower M et al. Atazanavir: 12 months of clinical experience in 241 individuals. 10th EACS, Dublin 2005. Abstract PE7.9/9.